fix: pylint errors

Author: tomplus

kubernetes_asyncio/watch/watch_test.py

@@ -164,7 +164,7 @@ async def test_unmarshall_k8s_error_response(self):
 
         with self.assertRaisesRegex(kubernetes_asyncio.client.exceptions.ApiException,
                 '\(410\)\nReason: Gone: too old resource version: 1 \(8146471\)'):
-            ret = Watch().unmarshal_event(json.dumps(k8s_err), None)
+            Watch().unmarshal_event(json.dumps(k8s_err), None)
 
     def test_unmarshal_with_custom_object(self):
         w = Watch()